Create Sessions DB
Add commented-description for ProductLookup module
Refactor ProductLookup to handle batch requests up to 10 products (Amazon limit)

* Add File responsibility description
* Rename load_from_asin to load_product_batch which receives an string with ASINs separated by comma and always return an Array
* Change get_request_object to include :similar_products
* Update file so it can be ran from the command line
create new session or assign current session to instance before every action
* created update_session method which will either create a new session or assign current session to an instance variable
* create generate_session_key to be assigned when creating new sessions
Add ASIN to the response and add default price when not present
fixing up sessions
Merge pull request #14 from ShopIt2Me/sim-prod-rltnshp

Change product attribute amzn_id to asin to more accurately model API in...
Merge branch 'master' into refactor_product_lookup
Update Rakefile db:seed to use ProductLookup module

* Update ProductLookup return description
* Handle Amazon edge cases when SimilarProducts has length of 1 (hash instead of an Array)
made changes to simple sessions
Merge pull request #15 from ShopIt2Me/refactor_product_lookup

Refactor product lookup
Merge branch 'master' into create_sessions

Conflicts:
	db/schema.rb
fixed merge conflicts